Why do videos converted from FLV not behave nice in editors?

[resonatored]

im trying to do some editing (basic cut and pasting) in windows movie maker, with videos ive converted from FLV

ive converted to heaps of different types of video (mpg, mpeg, avi, wmv..)

and most convert fine. (using different latest build converters, total video converter, AVS 6, Super C)

but after importing into movie maker, traversing frames and moving round the timeline is painfull

im a noob with video internals but it seems like the video doesnt have an index? or something.. when you click in the timeline to go to a paticular frame it does nothing so you click along a bit more and then the preview window maybe displays the (possibly)right frame.

ive never had that problem with videos that i havent converted, could someone tell me if FLVs are lacking something that is supposed to carry across in the conversion process. or a fix for this problem?

cheers

[guns1inger]

Many formats, of which FLV is a prime example, are designed for the highest possible compression for end user playback. The techniques used to gain this level of compression come at a price. The price is that these formats are very poor for editing. Most of the formats you have described (mpg, wmv, AVI compressed with Xvid/Divx) fall into this category. Some have specialised editor that can get around some of the inherent problems with a particular format (WMM for WMV, VideoRedo for Mpg, for example), but they don't solve issues such as compounded encoding and compression artifacts arising.

However, when you convert one video format to another, the characteristics of the new video are based on the new video format. This means that a new index is created if the new format requires and index. If you have converted you FLV files to another format that you have edited successfully before, and it is not working, look to your tools and your process. The problem lies not in the FLV, but how you are creating your new source. Only if you were editing the FLV file itself could you claim it to be the cause.

[Baldrick]

It's probably because you are using video formats/settings with few keyframes. Try instead convert the flv to edit friendly video codecs like dv, mjpeg, huffyuv, lagarith, uncompressed, raw and not divx,xvid,h264 etc.

[resonatored]

thankyou both for your answers, they helped heaps. ive used mjpeg and its behaving fine now.

[redwudz]

Just to add, highly compressed formats like Divx/Xvid have keyframes about every 300 frames by default. A keyframe is a complete frame of video. The rest of the frames between are only partial frames. For a clean cut or paste, you need to do it at the keyframe interval, or you need to re-encode at the cut, or re-encode the whole video. The keyframe interval may also affect scrolling through the video, depending on the editor used and the format.

With a low keyframe interval rate, you can see that frame accurate editing may be difficult. If you throw in VBR video or audio, it gets even worse. I don't use FLV or WMV much, but they likely share these characteristics.

As mentioned, if you want to do extensive editing, a low or no loss codec is the best choice. Then you can cut wherever you want and editing will be much easier.

A program like Gspot can show you the keyframe interval for most formats.

And welcome to our forums.

[resonatored]

thanks redwudz, quality info, cheers everyone for your help. ill definitely be back here if i need any further help.

thanks again